So when I was watching this anime I was wondering - even though all the Norma are women and they are stuck on that island, is it still possible for them to have kids? And I also wonder, did any Norma have kids in the past?
from the crossange wiki, you can get this
Norma (ノーマ Nōma?) is the name given to those who are born without the ability to use Light of Mana. Like the Ancient Humans, they cannot use Mana and will destroy anything made out of Mana just simply by making physical contact with it. Unlike Ancient Humans, Norma can be born of parents that can use Mana and are an example of a genetic throwback to the time where all humans couldn't use mana. Only female can be Norma, the reason why is unknown.
notice this line
Unlike Ancient Humans, Norma can be born of parents that can use Mana
it says that norma can be born with parents who can use mana and that's practically the only difference between norma and ancient humans show in the wiki. therefore, if ancient humans can have children, then norma should be able to have children, also note that there is nothing that states that normas can't have children so i don't know where the question is coming from but hope this helps a bit.
here is the link to the page http://crossange.wikia.com/wiki/Norma